Won't charge above 71%

My z3tc LTE won't charge above 71% - anyone seen something like that? I've left it overnight, no luck.

I'm using a root-exploited 5.0.2 ROM (I downgraded from 5.1.1. which had the same problem but WiFi wonkiness). I could try stock FTF but it's a pain to bring it back to root...thoughts?